You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
90 lines
1.6 KiB
90 lines
1.6 KiB
10 months ago
|
use std::collections::HashSet;
|
||
|
use std::collections::VecDeque;
|
||
|
|
||
|
type Str = VecDeque<u8>;
|
||
|
type Res = HashSet<u32>;
|
||
|
|
||
|
fn pr(s: &Str) {
|
||
|
for c in s.iter() { print!("{}", c); }
|
||
|
println!("");
|
||
|
}
|
||
|
|
||
|
fn is_prime(k: u32) -> bool {
|
||
|
if k < 0 {
|
||
|
return false;
|
||
|
}
|
||
|
for i in 2..k {
|
||
|
if k % i == 0 {
|
||
|
return false;
|
||
|
}
|
||
|
}
|
||
|
return true;
|
||
|
}
|
||
|
|
||
|
fn nstr(n: u32) -> Str {
|
||
|
let mut res = Str::new();
|
||
|
let mut nn = n;
|
||
|
while nn > 0 {
|
||
|
res.push_front((nn % 10) as u8);
|
||
|
nn /= 10;
|
||
|
}
|
||
|
res
|
||
|
}
|
||
|
|
||
|
|
||
|
fn strn(s: &Str) -> u32 {
|
||
|
let mut res = 0;
|
||
|
for d in s.iter() {
|
||
|
res *= 10;
|
||
|
res += *d as u32;
|
||
|
}
|
||
|
res
|
||
|
}
|
||
|
|
||
|
|
||
|
fn test(s: &Str, hs: &mut Res) {
|
||
|
let n = strn(s);
|
||
|
if is_prime(n) {
|
||
|
//println!("{}", n);
|
||
|
hs.insert(n);
|
||
|
}
|
||
|
}
|
||
|
|
||
|
fn sp(s: &Str, fx: usize, k: usize) -> Str {
|
||
|
let mut res = Str::new();
|
||
|
for i in 0..fx {
|
||
|
res.push_back(s[i]);
|
||
|
}
|
||
|
res.push_back(s[k]);
|
||
|
for i in fx..s.len() {
|
||
|
if i != k { res.push_back(s[i]); }
|
||
|
}
|
||
|
res
|
||
|
}
|
||
|
|
||
|
fn lp(s: &Str, fx: usize, keep_first: bool, hs: &mut Res) {
|
||
|
let kf = 0; //if keep_first { 0usize } else { 1usize };
|
||
|
for k in (fx + kf)..s.len() {
|
||
|
let ss = sp(&s, fx, k);
|
||
|
//count += 1;
|
||
|
if ss != *s || keep_first {
|
||
|
test(&ss, hs);
|
||
|
}
|
||
|
lp(&ss, fx + 1, false, hs);
|
||
|
}
|
||
|
}
|
||
|
|
||
|
fn main() {
|
||
|
let mut hs = HashSet::new();
|
||
|
let mut s = nstr(1234567); // manual test of length
|
||
|
let mut max = 0;
|
||
|
let m = lp(&s, 0, true, &mut hs);
|
||
|
for h in hs.iter() {
|
||
|
if *h > max {
|
||
|
max = *h;
|
||
|
}
|
||
|
}
|
||
|
println!("{}", max);
|
||
|
}
|
||
|
|